Skin cancer

It's the ultraviolet radiation (UVR) in sunlight that causes more than 95 percent of skin cancers. UVR causes sunburn, damage to the genetic make-up of the skin, premature ageing and, in the long-term, increases skin cancer risk.

Your risks of skin cancer increase:

• If you have been exposed to sun as a child.
• If you work outside, especially in the middle of the day.
• If you have been regularly sunburnt.
• If you live closer to the equator.
• If you have fair or red hair, blue eyes and freckles.
• If you have a family history of skin cancer.
• If you have many moles (the more moles, the greater the melanoma risk).

Most cancers can be prevented by protecting the skin from sunlight. People who have already had a skin cancer or keratoses (sun spots) are at increased risk. Short periods of intense exposure to sunlight or sun beds increase the risk of melanoma. More common skin cancers also show up as new lumps or bumps of any colour; red areas; crusty, scaling spots or scabs; dry, rough areas of skin; spots or lumps that bleed easily when rubbed with a towel; erosions or ulcers (sores that don't heal properly) or a growing scar-like area.

Types of skin cancer

Of the three main types of skin cancers, basal cell carcinoma (BCC) is the most common and least dangerous. On the face, head or neck they most often start off as small round or flattened lumps, which may be red, pale or pearly and may have tiny vein-like blood vessels on the surface. On the trunk and limbs they are more often slow-growing red dry patches. A sore or ulcer can appear in the middle of the lump, even at an early stage. Those who have had one BCC are at more risk of developing another.

Squamous cell carcinoma (SCC) is less common than BCC and invasive SCC can be more dangerous. It is most likely on areas exposed to sun (face, hands and legs). It is most serious if it appears on the lip or on the ear. An SCC appears as a scaly nodule that may bleed and ulcerate. Sometimes it can spread to the lymph nodes. SCCs and BCCs can vary in size from a few millimetres to several centimetres. Invasive (deeper) SCCs often begin in sun spots, which are dry, rough non-cancerous spots.

Malignant melanoma (MM) is the least common but most dangerous skin cancer and is more common in people over 50. It usually starts as a new or changed spot, freckle or mole that changes colour, thickness or shape over some months. Melanomas can be various colours: black, dark brown, red, blue-black or a combination, and they may be irregular in shape or outline. They can develop in existing moles. Melanomas can spread to internal organs and cause death if not detected early and removed.

Treatment for skin cancers

Some scarring is likely after most forms of skin cancer treatment. If a large skin cancer is removed, skin grafting may be needed. Some tumours are treated with radiotherapy.

• BCCs and SCCs
  Treatment of BCCs (basal cell carcinoma) depends on the type of tumour, where it is, how big it is and how advanced its development. Invasive SCCs (squamous cell carcinoma) are nearly always treated surgically.

  Options for solar keratoses and other in situ SCCs and BCCs include excision (cutting and stitching), cryotherapy (freezing), shaving, curettage and cautery, radiotherapy, application of 5-Fluorouracil cream or treatment of the tumour with a photosensitising chemical in a cream which is then exposed to light). Immune modulators (imiquimod cream and interferon injections) may be used to remove superficial skin cancers with minimal scarring. Laser treatment can also be used.

• MM
  Malignant melanomas can be deadly, spreading to other organs. Treated early by surgical removal, there is a 95 percent chance of a cure. Risk of recurrence increases with the depth of melanoma cells.

  Malignant melanoma needs to be surgically removed, rather than burnt or frozen off. The tumour is cut out along with an additional margin of normal skin and the wound is then stitched. Often this is done in two stages.

  The portion removed is sent to pathology for testing to measure how deeply into the skin the cancer cells have penetrated. The deeper the cells, the more likely they have spread to the lymph nodes or internal organs.

  If this is suspected, other tests may be ordered, including lymph node biopsy, blood tests, a chest X-ray and scans. Risk of recurrence increases with the depth of cells.

All material is © Media 21 Publishing, and originally appeared in the October 2006 issue of Good Medicine magazine.